Suzuki Club UK

This old dog was about to fill his gearbox diffs etc with a load of acquired oil but noticed in small print ( Not for manual) Looked up the oil grade and found it was api gl-5. Didn't mean a lot to me but after digging on the net found that though a good oil it eats yellow metal/ brass. Manual gearbox's should only have api gl-4. Next, go to buy correct oil and on the container it said for some manuals but also in the small stuff api gl-5. Now confused.
Some oil companies say api gl-5 can be used but reports on the web said that when analyzing drained oil there was more yellow/ brass in oil from gearbox's using gl-5 than ones using gl-4 and that the Synchromesh rings would wear to the point of not working .
OK, I suppose you all knew all this but I am from the old school and oil was just thick or thin. So the old dog has learnt a new trick- it might not do what it says on the tin.

You can get yellow metal safe Gl-5 but that one sounds like it isn't, not all gearbox's use brass/bronze syncros therefore some are fine with GL5....vitaras aren't.


Use GL4 in the gearbox and the tbox and diffs are fine with GL5

LJ80 use brass syncros so will stay well clear for the gearbox but have used it in the diffs.